1. Technical Field
This disclosure generally relates to thermoelectric devices and more particularly to thermoelectric devices having a respective electrical current and a respective thermal gradient aligned approximately parallel or anti-parallel.
2. Description of the Related Art
Microprocessors, laser diodes, and other electronic devices generate heat during operation, which may adversely affect the performance of these devices. Electronic devices may be cooled by passive or active cooling systems. Passive cooling systems, which include heat sinks and heat pipes, dissipate heat. Design considerations in determining whether an electronic device can be cooled by a passive cooling system include the size requirement of the passive cooling system, the amount of ventilation at the passive cooling system, the operating temperature of the electronic device and the ambient temperature range where the device will be operated. Passive cooling systems might not be appropriate for many small electronic devices where the passive cooling system would require too much space or in devices where there is an insufficient amount of ventilation to dissipate the heat.
Active cooling systems may include refrigerators, e.g., mechanical vapor compression refrigerators, and thermoelectric coolers. Refrigeration based cooling systems generally require significant hardware such as a compressor, a condenser and an evaporator and require a relatively large amount of space. In addition, refrigeration based cooling systems include a large number of moving mechanical parts, which may be costly and which may require maintenance. In many electronic devices, it would be impractical and commercially non-viable to have refrigeration based cooling systems. Consumers may avoid purchasing an electronic device that needs to be maintained.
Active cooling systems also include thermoelectric cooling systems such as a Seebeck-Peltier (hereinafter “Seebeck”) device. Seebeck devices provide cooling (or heating) by passing an electrical current through a thermoelectric device. A typical Seebeck thermoelectric device includes a layer of a Seebeck effect material, which conducts electricity, and another layer of an electrical conductor. When a voltage is applied across the terminals of a Seebeck thermoelectric device, heat is absorbed or produced at the interface of the Seebeck effect material and the other electrical conductor, depending on the direction of the electrical current flow.
Seebeck thermoelectric devices offer many advantages over refrigeration based cooling systems. Seebeck thermoelectric devices may be relatively small, have no moving parts, may be operated in harsh environments such as a vacuum, and may be operated in any orientation. Thus, Seebeck thermoelectric devices may be utilized for providing solid-state cooling of small electronic devices. However, current Seebeck thermoelectric devices require cumbersome electrical connections and are not as efficient for their size as some of the other cooling systems.
There is a need for improved Seebeck thermoelectric devices.